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Re: FM timbre

Date1997-11-05 16:10
FromRussell Pinkston
SubjectRe: FM timbre
You should provide a complete score, not just the f-cards. Otherwise no-one
can test what you're doing.

Regards,
Russell Pinkston

>Hi,
>    Whilst looking into the effect of the first fraction of time upon 
>perception of the whole timbre of a sound I have been playing with 
>some very simple FM synthesis scores. I'm very puzzled now. The .ORC 
>that follows is a standard single carrier FM orchestra, and two 
>.SCO's follow. I thought that the difference in tone and timbre 
>percieved in the two was a result of the initial time segments 
>differing, but the difference is an actual characterisic of the whole 
>sound. If the resulting sound files from each are edited to have the 
>first part removed, they still sound very different. What am I 
>missing here, how can they be physically different in the latter 
>stages ??
>
>
>
>;
>;			     Single Carrier FM				      ;
>; 
>;    Specific values and basic design come from John Chowning's
>article       ; ;  "The Synthesis of Complex Audio Spectra by Means of
>Frequency Modulation"  ; ;; ;	   coded by Richard Boulanger - Berklee
>College of Music	      ; ;
>
>instr 1
>   ; p4  = amplitude of output wave
>   ; p5  = carrier frequency in Hz
>   ; p6  = modulating frequency in Hz
>   ; p7  = modulation index 1
>   ; p8  = modulation index 2
>   ; p9  = carrier envelope function
>   ; p10 = modulator envelope function
>
>   i1 = 1/p3			     ; one cycle per duration of note
>   i2 = p7 * p6 		     ; calculates deviation for index 1
>   i3 = (p8-p7) * p6		     ; calculates deviation for index 2
>
>   ampcar  oscil   p4,i1,p9	     ; amplitude envelope for the carrier
>   ampmod  oscil   i3,i1,p10	     ; amplitude envelope for the
>   modulator
>
>   amod    oscili  ampmod+i2,p6,1    ; modulating oscillator
>   asig    oscili  ampcar,p5+amod,1  ; carrier oscillator
>        out     asig
>endin
>
>;score one
>
>f1 0 1024 9 1 1 0
>f2 0 513 7 1.04 21.63 .56 149.43 .54 85.37 .54 85.53 .54 85.53 .54
>85.53 .54
>f3 0 513 7 .54 85.54 .54 85.53 .54 85.37 .54 85.53 .54 85.53
>.54 85.53 .54 i1 0 0.5 10000 440 400 10 15 3 2 e
>
>; score two - difference is in p5 of f2 (.55 instead of 1.04)
>f1 0 1024 9 1 1 0
>f2 0 513 7 .55 21.63 .56 149.43 .54 85.37 .54 85.53 .54 85.53 .54
>85.53 .54
>f3 0 513 7 .54 85.54 .54 85.53 .54 85.37 .54 85.53 .54 85.53
>.54 85.53 .54 i1 0 0.5 10000 440 400 10 15 3 2  e
>
>
>*************************************************
>Peter Kearton,
>University of Surrey Psychology Department,
>Guildford,
>United Kingdom.
>GU2 5XH
>Tel. UK (01483) 259437
>e-mail - P.kearton@surrey.ac.uk
>*************************************************
>
>

----------------------------------
Russell F. Pinkston, D.M.A.
Associate Professor of Composition
Director, Electronic Music Studios
School of Music
The University of Texas at Austin
Austin, TX 78712

[512-471-0865]